Boil potatoes in salted water, allow to cool down, peel them and cut into slices.
Cut leeks into rings. Peel carrots and cut into pieces. Peel and chop the celery. Blanch carrots and celery.
Peel the shallots and garlic. Chop garlic. Champigons half or quarters depending on size.
Fry potato in oil, add shallots and fry slowly.
Add mushrooms and vegetables and continue frying. Season with salt, pepper, tarragon and marjoram.
Serve garnished with chives.